An incandescent lamp, and in particular a tungsten halogen lamp is generally comprised of a lamp capsule in the form of a sealed envelop of vitreous material having a bulb portion and a press-sealed portion, and a lamp base which is typically a ceramic base for holding the lamp capsule. Lamps of this very general type are shown in the following U.S. Pat. Nos.: 3,431,540; 4,145,631; 4,243,907; 4,499,404; and 4,568,854. In these lamp constructions, the lamp capsule typically has associated therewith a pair of electrically conductive lead-in wires that are hermetically sealed through the press-sealed portion in spaced-apart relationship to one another and extending beyond the press-sealed portion with the lead-in wires connected to a filament structure positioned within the bulb portion. The conductive lead-in wires are typically molybdenum wires.
In the existing lamp construction, the lamp capsule is assembled in the ceramic base in the following manner. The molybdenum leads are sand blasted and then trimmed to the correct length. Lead wires are welded to the molybdenum leads of the capsule. Contact pins are staked into the ceramic base forming a ceramic base subassembly. The lead wires welded to the molybdenum leads are dipped into a solder flux and inserted into the contact pins supported in the ceramic base. The lead wires are inserted into the pins to a proper depth with the use of a fixture to set the approximate light center position. The lead wires are soldered to the contact pins by dipping into a lead-zinc solder (95:5 ratio) and excess wire is trimmed flush with the end of the contact pin. The lamp light center is set on a comparator by positioning the filament in a box by hand. The base is then filled with cement and the lamp is inserted into an oven to cure the cement.
There are several drawbacks and disadvantages associated with this prior art method of assembly. The weld between the lead wires and the molybdenum leads may become broken when setting the light center position. The step of welding the lead wires to the molybdenum leads is generally somewhat difficult to carry out. The lead wires must be welded parallel to the molybdenum leads. There is generally a poor appearance of the finished assembly due to the lead wires being welded to one side of the molybdenum leads extending from the lamp capsule. Errors may also develop, requiring reworking of lamp assembly due to an improper positioning of the light center height during the soldering operation. Also, it is generally a relatively difficult procedure to stake the pins in the ceramic base in a secure manner.